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1.
V. M. Pinchuk E. S. Kotlyarova N. V. Parkhomenko P. N. Tsybulev 《Journal of Structural Chemistry》1996,37(4):544-556
The studies concerned with the oxidation of carbon monoxide on the nickel surface are reviewed. The Eley-Rideal (ER) collision
and Langmuir-Hinshelwood (LH) adsorption mechanisms of the oxidation are analyzed. Calculations of the activation barriers
of the oxidation of carbon monoxide on the Ni (111), (100), and (110) faces were performed for the first time and involved
optimization of the reaction paths by the collision and adsorption mechanisms. It is shown that on the Ni (111) and (110)
faces the ER collision mechanism of the reaction is preferable with the activation barriers ΔE
dis
O
2=62 kJ/mole and ΔE
trans
O
A21F50012x=25 kJ/mole for Ni (111) and ΔE
dis
O
2=72 kJ/mole and ΔE
trans
O
2=20 kJ/mole for Ni (110); on the Ni (100) face, the LH adsorption mechanism with the activation barriers ΔE
dis
O
2=75 kJ/mole and ΔE
trans
O
2=42 kJ/mole is favored. Analysis of the potential barriers for the catalytic oxidation of carbon monoxide on the Ni surfaces
suggests the LH mechanism to be preferential, although insignificant differences in the activation barries can lead to the
oscillatory reaction mechanism, which is confirmed experimentally. The calculations were performed by the LCAO MO SCF method
in the MINDO/3 approximation.
Kiev Polytechnical Institute. Translated fromZhurnal Struktumoi Khimii, Vol. 37, No. 4, pp. 628–645, July–August, 1996.
Translated by I. Izvekova 相似文献
2.
A. M. Tokmachev Yu. N. Pushkar A. V. Fionov E. V. Lunina N. D. Chuvylkin 《Russian Chemical Bulletin》2000,49(6):991-996
The results of ESR investigations and quantum-chemical studies on the coordination of 2,2,6,6-tetramethylpiperidine-N-oxyl to the Lewis acid sites (LAS) on the surface of gallium oxide are reported and analyzed. The structural, spin, electrostatic,
and energy characteristics of the coordination of the simplest nitroxyl radical, H2NO., to the Ga(OH)3 model cluster-type LAS were calculated by the unrestricted Hartree—Fock method in the 6–31G basis set and using the semiempirical
PM3 approximation. The properties of gallium-containing nitroxyl surface complexes and their aluminium-containing analogs
are compared. According to the results of cluster quantum-chemical calculations, the LAS on the surface of gallium oxide are
stronger than those on the alumina surface.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 996–1001, June, 2000. 相似文献
3.
This paper gives the results of quantum chemical MINDO/3 calculations of carbon monoxide adsorption on the ZnO polar (0001)
surface. The energetically most favorable one-center adsorption of carbon monoxide on the ZnO (0001) surface occurs by the
electron density transfer from the lone electron pair of CO carbon to the vacant orbital of the Zn
3C
2+
cation. The calculated heat of CO adsorption, dependent on the type of covering, and the stretching frequency υCO are in good agreement with the available experimental data.
Institute of Catalysis, Siberian Branch, Russian Academy of Sciences. Ruhr University, Bochum, Germany. Translated fromZhurnal Strukturnoi Khimii, Vol. 35, No. 1, pp. 12–16, January–February, 1994.
Translated by L. Smolina 相似文献
4.
M. R. Baklanov A. A. Karpushin K. P. Moginikov A. N. Sorokin 《Journal of Structural Chemistry》1996,37(1):11-17
We used the AM1 quantum chemical and cluster models to study the mechanism of formation of a SiF2-like layer and dissociation of the Si−Si bond during the interaction of atomic fluorine with the (111) surface of silicon.
It is shown that the negatively charged (Si3−Si−F2)− complex with the five-coordinated centered silicon atom plays an important part in these processes. The above complex participates
in the interaction of atomic fluorine with silicon to form a SiF2-like layer and break the subsurface Si−Si bonds without penetration of fluorine atoms into the subsurface silicon layers.
Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 1, pp. 14–21, January–February, 1996.
Translated by I. Izvekova 相似文献
5.
Additional electron emission that reflects specific properties of ferroelectrics was detected after the negatively charged
surface of these preliminarily polarized materials was exposed to soft X-radiation (hv) ≤3 kV). The properties of this emission, which is referred to as anomalous electron emission (AEE) and is excited in single-crystal
and ceramic samples, are studied with a standard X-ray photoelectron spectrometer. It is shown that the parameters of AEE
spectra correlate with the characteristics of the materials. The conclusions of the phenomenological theory of the phenomenon
are in satisfactory agreement with the experimental results.
Translated fromZhurnal Strukturnoi Khimii, Vol. 39, No. 6, pp. 1031–1036, November–December, 1998 相似文献
6.
A. G. Filatova I. O. Volkov N. I. Krikunova T. A. Misharina R. V. Golovnya 《Russian Chemical Bulletin》2000,49(2):314-316
The surface composition and surface microtopography of corn starch cryogels obtained from a 3% starch sol containing organic
flavoring agents were studied by X-ray photoelectron spectroscopy and scanning electron microscopy. The cryogels withn-octanol,n-octyl methyl ketone, andn-octyl acetate have a well-developed microtopography and their surface layer (5–20 nm) is enriched in sorbed compounds.n-Octyl acetate, unliken-butyl acetate, influences the composition and microstructure of the cryogel surface. The sorbedn-octyl acetate occupies 20–25% of the surface, which has a well-developed topography and a porous structure. Drying and evacuation
do not change the concentration of the organic sorbates having a C8 alkyl group in the surface layer.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 312–314, February 2000. 相似文献
7.
XRD is used to determine the structure of Cp′Ir(cod) at a temperature of 150(2) K. Crystallographic data for C14H19Ir are: a = 10.8272(5) ?, b = 9.7746(4) ?, c = 10.9180(5) ?, β = 97.3310(10)°, monoclinic symmetry, space group P21/n, V = 1146.02(9) ?3, Z = 4, d
calc= 2.199 g/cm3, R = 0.0246. The structure is molecular, built of neutral molecules. The metal atom coordinates carbon atoms of two cyclic ligands:
5-methylcyclopentadienyl-ion (Cp′) and 1,5-cyclooctadiene (cod). Five Ir-CCp′ distances lie in the range of 2.21–2.28 ?; four Ir-Ccod distances differ insignificantly, and their average value is 2.114(13) ?. The C11C12C13C14C15 and C1C2C5C6 planes of ligand fragments are almost parallel, and the angle between normals is 1.9°. In the crystal, molecules are bonded
only by van der Waals interactions; in the structure, the eight shortest Ir...Ir distances are in the range of 5.608–7.257
?.
Original Russian Text Copyright ? 2009 by K. V. Zherikova, N. B. Morozova, and I. A. Baidina
__________
Translated from Zhurnal Strukturnoi Khimii, Vol. 50, No. 3, pp. 591–594, May–June, 2009. 相似文献
8.
N. I. Medvedeva V. P. Zhukov D. L. Novikov V. A. Gubanov 《Journal of Structural Chemistry》1996,37(1):41-50
The band structure of the fluorite-type δ-Bi2O3 was calculated by the linear LMTO methods in the approximation of overlapping atomic spheres using the basis set of orthogonal
orbitals (LMTO-ASA) and by the full-potential LMTO method (LMTO-FP) for two vacancy orientations over a wide range of oxygen
concentrations. The calculated parameters of chemical bonds—the binding energy Ebin and the pressure of the electron-nuclear system—show that the most stable compound is that with two vacancies per unit cell,
oriented predominantly along the (111) direction. The hybrid Bi−O bonds are weak, and mostly the Bi−Bi bonds are responsible
for the structural stabilization of δ-Bi2O3. The mechanism of the formation of a semiconductor gap in the band structure of δ-Bi2O3 is discussed.
Institute of Solid State Chemistry, Ural Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 1, pp. 48–58, January–February, 1996.
Translated by I. Izvekova 相似文献
9.
O. V. Yaltychenko 《Journal of Structural Chemistry》1994,35(6):792-798
The soliton approximation is examined for mixed-valence dimers and trimers with one migrating electron. The calculations use
Hamilton's canonical equations and a time-dependent wave function of the soliton type. In the two limiting cases (strong and
weak vibronic coupling), the soliton approximation correlates well with the exact analytical solution. As in the adiabatic
approximation at g2/v=1, the delocalized limit (quasifree electron) is transformed to the localized one (electron locked on the center). For
molecular trimers, the soliton approximation allows us to reveal the cases where the transfer of an electron from the first
to the third center is accompanied by electron density concentration on the intermediate center.
Institute of Chemistry, Academy of Sciences, Moldova Republic. Translated fromZhurnal Strukturnoi Khimii, Vol. 35, No. 6, pp. 46–53, November–December, 1994.
Translated by L. Smolina 相似文献
10.
H. Ohshima 《Colloid and polymer science》1999,277(6):563-569
An exact analytical expression for the potential energy of the electrostatic interaction between a plate-like particle 1
and a cylindrical particle 2 of radius a
2 immersed in an electrolyte solution of Debye–Hückel parameter κ is derived on the basis of the linearized Poisson–Boltzmann
equation without recourse to Derjaguin's approximation. Both particles may have either constant surface potential or constant
surface charge density. In the limit of κa
2→0, in particular, the interaction between a plate with zero surface charge density and a cylinder having constant surface
charge density becomes identical to the usual image interaction between a line charge (a charged rod of infinitesimal thickness)
and an uncharged plate.
Received: 22 September 1998 Accepted in revised form: 27 January 1999 相似文献
11.
Adsorption of iodide ions at the Bi(111) and Cd(0001) electrodes from the aqueous solutions with constant ionic strength 0.1x M KI + 0.1(1−x) M KF and 0.1x M KI + 0.033(1−x) M K2SO4 has been studied by impedance spectroscopy. It was found that, to a first approximation, the classical Frumkin–Melik–Gaikazyan
equivalent circuit with the slow diffusion-like and adsorption steps can be applied for fitting the experimental impedance
data for iodide ions adsorption on Bi(111) and Cd(0001) from aqueous solutions with constant ionic strength. The modified
Grafov–Damaskin circuit can be used in the region of electrode potentials, where parallel faradic processes (electroreduction
of protons, oxygen traces) are probable. The more complicated Ershler equivalent circuit, taking into account the slow diffusion-like,
adsorption and charge transfer steps, is not applicable for characterization of the adsorption process of I− at Bi(111) and Cd(0001) electrodes. 相似文献
12.
É. I. Zen’kevich Th. Blaudeck M. Heidernätsch F. Cichos C. von Borczyskowski 《Theoretical and Experimental Chemistry》2009,45(1):23-34
The quenching of photoluminescence (PL) in semiconducting CdSe/ZnS and CdSe nanocrystals (NC) of various sizes during surface
passivation by molecules of tetrapyridylporphyrins (P) in toluene at 295 K was investigated. It was shown that resonance transfer
of energy NC → P plays a minor role in PL quenching (<10%), while photoinduced electron transfer NC → P is absent. On the
basis of experimental data and quantum-mechanical calculations it was established that with identical molar ratio x = CP/CNC the probability of quenching k
q
decreases with increase in the size of the NC while the PL quenching process itself under conditions of quantum confinement
is due to electron tunneling of the excited electron–hole pair on the surface of the NC followed by localization of the organic
ligand (P) on anchor groups. The obtained results are of interest for investigating the mechanisms of the blinking of PL in
single semiconductor nanocrystals.
Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 45, No. 1, pp. 17–26, January–February, 2009. 相似文献
13.
A new approach to calculating the equilibrium characteristics of the adsorption of noble gases on the amorphous surfaces of
adsorbents was developed and applied to the Ar−TiO2(rutile) system. Intermolecular adsorbate-adsorbate interactions are taken into account for the nearest neighbors in the quasi-chemical
approximation. The lattice energy parameters of all interactions of the model are determined from the Lennard-Jones potential
(12-6). The formation of amorphous TiO2(rutile) surface includes completion of the surface layers and partial removal of the surface oxygen ions. The quality of
the amorphization procedure was confirmed by the experimentally measured heats and isotherms of adsorption of the system under
study.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1109–1118, June, 1997. 相似文献
14.
The enrichment with ruthenium of the surface layer of a Pd−Ru alloy tube during the propane hydrogenolysis was observed. Metal
particles immobilized within carbonaceous deposits and filamentous crystals of the metals with a carbon cover are formed on
the Rh and Ir wires. Thermal treatment in gases free of carbon compounds does not cause such a deep reconstruction. The deep
reconstruction occuring during the propane hydrogenolysis is the stronger, the greater the amount of carbon this metal dissolves.
Dedicated to the memory of Academician M. E. Vol'pin timed to his 75th birthday.
Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 6, pp. 1100–1103, June, 1998. 相似文献
15.
The structure of Ir(CO)2(acac) is determined by XRD at room temperature. Crystallographic data for C7H7IrO4 are: a = 6.4798(5) ?, b = 7.7288(5) ?, c = 9.1629(10) ?, α = 105.738(2)°, β = 90.467(3)°, γ = 100.658(2)°, space group 1, P
, V= 433.24(6) ?3, Z = 2, d
calc = 2.662 g/cm3, R = 0.0167. The structure is built of isolated mononuclear molecules. The central iridium atom has a square coordination environment
formed by two oxygen atoms that belong to the acetylacetonate ligand and two carbon atoms of carbonyl groups. The average
Ir-O and Ir-C bond lengths are 2.045(3) ? and 1.832(6) ? respectively. Molecules are stacked in such a way that the planes
of coordination squares turn out to be parallel to the Ir...Ir distances between the nearest neighbors in the stack of 3.242
? and 3.260 ?.
Original Russian Text Copyright ? 2009 by K. V. Zherikova, N. V. Kuratieva, and N. B. Morozova
__________
Translated from Zhurnal Strukturnoi Khimii, Vol. 50, No. 3, pp. 595–597, May–June, 2009. 相似文献
16.
A technique for the production of perfect thin-layered Ir coatings on inert Ti supports is developed. The highly textured coatings have some potential uses. Local topography and energy nonuniformness of the surface of such Ir electrodes are studied by electrochemical scanning tunneling microscopy (ESTM) and scanning tunneling spectroscopy (STS). In situ STM images of Ir–Ti textured electrodes with axial texture (111) are obtained with an atomic resolution at potentials of 0.3 to 1.2 V, in 0.05 M H2SO4 as well. Energy states of surfaces of Ir–Ti textured electrodes are studied with an atomic resolution using in situ STS by distance and voltage. Dependences of the tunneling current on the tunneling voltage and the tunneling-gap width are measured at Ir-surface potentials of 0.3 to 1.2 V. Effective potential barrier for the electron tunneling is estimated at different potentials of Ir. 相似文献
17.
A. N. Shmakov S. V. Mytnichenko S. V. Tsybulya L. P. Solovyeva B. P. Tolochko 《Journal of Structural Chemistry》1994,35(2):224-228
A high-resolution powder diffraction station with synchrotron radiation has been created. The diffractometer was developed
on the basis of two Microcontrol precision goniometers. The latter provide the independent movement of a specimen and a detector
with a minimal step of 2θ=0.001°. Using the Si(111) crystal as the analyzer, we obtained half widths of the (212), (203),
and (301) reflections for α-SiO2 (0.02–0.025° 2θ). The device was tested using α-Al2O3 as the standard.
Institute of Catalysis, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 35, No. 2, pp. 85–91, March–April, 1994.
Translated by T. Yudanova 相似文献
18.
E. N. Shaposhnikova E. A. Avetisyan S. R. Sterlin N. N. Bubnov C. P. Solodovnikov A. L. Chistyakov I. V. Stankevich B. L. Tumanskii 《Russian Chemical Bulletin》1997,46(11):1851-1854
The kinetics of hydrogen abstraction from hydrocarbons by the air-stable perfluoroacetyldiisopropylmethyl radical was studied
by ESR, and a reaction mechanism was proposed. The degree of delocalization of the unpaired electron in the model C(5)F3−C(1)·[C(2)(O(4))C(3)F3]C(6)F3 radical was calculated by the MNDO/PM3 method in the UHF approximation. For the conformation in which the CO group lies in
the plane passing through the C(1), C(2), and C(5) atoms, the electron density on the O atom is 0.22.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1954–1957, November, 1997. 相似文献
19.
A. A. Pribylov I. A. Kalinnikova S. M. Kalashnikov G. F. Stoeckli 《Russian Chemical Bulletin》2000,49(4):692-700
The isotherms of excess adsorption of CH4 (atP=0.001–160 MPa), SF6 (atP=0.001–2.4 MPa), and C6H6 (atP=0.0001–0.1 MPa) on carbon adsorbents—microporous carbons CMS and FAS with developed mesoporosity and graphitized soot—were
measured in the 298–408 K temperature region. Calculation of the isotherms of absolute adsorption of the total content of
these substances requires knowledge of the adsorption volume, which was determined by different methods: by the Dubinin—Radushkevich
equation; by the experimental isotherm of excess adsorption and the equation of absolute adsorption; by the method using the
intersection of nonlinear isosteres of excess adsorption and isosteres of absolute adsorption; by the comparative plot of
values of the excess C6H6 adsorption ΓFAS—Γsoor; by the method using the difference of molecular radii of adsorptives and the surface of the specific adsorbent; and by the
calculation of the adsorption layer thickness using the FHH equation for mesoporous systems. The results of determination
of the adsorption volume for microporous systems of these carbons agree well with each other and with the passport data for
the adsorbents. Analysis of the results revealed the peculiarity of the sulfur hexafluoride adsorption related to the formation
of associates on the surface of the carbon adsorbents.
Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 4, pp. 688–696, April, 2000. 相似文献
20.
S. K. Ignatov A. A. Bagatur'yants A. G. Razuvaev M. V. Alfimov M. B. Molotovshckikova V. A. Dodonov 《Russian Chemical Bulletin》1998,47(7):1257-1265
The structural, electronic, and energy parameters of the metal-containing clusters (H3SiO)3Si−O−XMe
n
(X=H, B, Al, or Zn;n=0, 1, or 2), which model organometallic groups on a SiO2 surface modified with B-, Al-, and Zn-containing alkyls, have been studied by quantum-chemical methods. Full geometry optimization
for these clusters was carried out by the SCF MO LCAO method taking into account the electron correlation within the frameworks
of the MP2 and B3LYP schemes using the 6-31G(d) (6-311G(d) for Zn) basis set. The effect of the crystal environment was taken
into account in calculations of siliconoxygen clusters containing 10 and 30 silicon atoms using theab initio SCF/6-31G(d) and semiempirical MNDO-PM3 methods. Various modes of coordination and interactions of organometallic groups
with oxygen atoms of surface groups were studied. For the organoaluminum group on the surface, two stable conformations were
found, namely, the three-coordinate structure with the chain −O−AlMe2 ligand and the four-coordinate (quasicyclic) structure with the Al atom that forms two nonequivalent bonds with the O atoms
at the same Si atom. The four-coordinate structure is energetically more favorable. No stable structures were found for the
organoboron and organozinc fragments.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1296–1303, July, 1998. 相似文献